The present invention generally relates to a system and method for monitoring packaging machines and, more particularly, to monitoring the use of consumables in packaging machines, such as foam dispensing machines, that are configured to selectively use consumable materials at various consumable usage rates for forming different types of packaging devices in different modes of operation.
Foam dispensing machines are conventionally used for a variety of packaging operations, such as for packaging an object in a container so that the foam provides a cushioned protection on one or more sides of the object during subsequent handling. One common packaging operation that is used for on-demand protection of packaged objects is foam-in-place packaging. In one foam-in-place packaging operation, a foam-forming composition is injected from a dispensing machine into a container, such as a corrugated board box, and the object, which is typically wrapped to prevent direct contact with the rising (expanding) foam, is surrounded by the foam as the foam expands to fill the void space between the object and the container. The foam-forming composition can be formed by mixing an isocyanate compound with a hydroxyl-containing material, such as a polyol (i.e., a compound that contains multiple hydroxyl groups), typically in the presence of water and a catalyst. The isocyanate and polyol precursors react to form polyurethane. At the same time, the water reacts with the isocyanate compound to produce carbon dioxide. The carbon dioxide causes the polyurethane to expand into a foamed cellular structure, i.e., a polyurethane foam, which serves to protect the packaged object.
A conventional automated apparatus for performing foam-in-place packaging produces foam-in-bag cushions by making bags from flexible plastic film and dispensing a foam-forming composition into the bags as they are being formed. As the composition expands to form a foam within a bag, the bag is sealed shut and typically is then dropped into a container holding the object to be cushioned. The rising foam again tends to expand into the available space, but does so inside the bag. Because the bags are formed of flexible plastic, they form individual custom foam cushions around the packaged objects. Exemplary types of such packaging apparatus are assigned to the assignee of the present application, and are illustrated, for example, in U.S. Pat. Nos. 4,800,708; 4,854,109; 5,027,583; 5,376,219; and 6,003,288, the entire disclosures of each of which are incorporated herein by reference. For example, foam-in-bag cushions can be formed using the SpeedyPacker™ foam-in-bag packaging system available from Sealed Air Corporation (Saddle Brook, N.J.). Packaging apparatuses, including the SpeedyPacker™ foam-in-bag packaging system, are further described in U.S. application Ser. No. 10/692,579, “Perforation Mechanism for a Foam-in-Bag Cushion and Method of Use,” the entire disclosure of which is incorporated herein by reference.
In some cases, the same apparatus or equipment can be used to dispense foam for different types of packaging operations. For example, a single packaging machine can be configured to operate in multiple modes according to the type of packaging to be performed. In a first mode, the machine can be used to form single bags of foam, commonly referred to as wet bags. In this mode, the machine can use a continuous supply of a plastic film sheet to form individual bags. Each bag has a bottom edge and side edges that are sealed, and the bag is filled with foam-forming materials before the top edge is sealed and simultaneously cut, thereby freeing the single bag from the remaining sheet of plastic film. The width of the wet bag is dependent upon the width of the roll of plastic film being used. Common widths for use with the SpeedyPacker™ system are 8, 12, and 19 inches. The length of the bag is determined by the machine operator and can vary depending upon the specific application. The same machine can also be operated in a second mode for producing continuous foam tubes (CFTs). A CFT is a length of multiple foam-filled bags that are still connected, the bags comprising the CFT being generally smaller in size than a typical wet bag. For example, a typical CFT pattern using 19-inch wide film would comprise bags that are approximately five inches in length. A CFT is prepared similarly to a wet bag with the exception that when the top of the bag is sealed after introduction of the foam-forming components, it is not cut free from the remaining length of plastic film. Instead, the bag remains attached to the advancing plastic film and another bag is formed immediately thereafter (i.e., the bottom seal for the next bag is made immediately above the top seal of the previous bag). In this manner, a series of interconnected foam-filled bags is produced. The foam-filled bags are connected by lengths of plastic film that are not foam filled, each length of film connecting the foam-filled bags typically being between about 0.25 inches and about 1 inch.
The same film and foam-forming materials are typically used by the machine in the different modes of operation. That is, the machine can be loaded with a supply of film and a supply of foam-forming materials to be used when forming either wet bags in the first mode of operation or the CFTs during the second mode of operation. Thus, the machine may be so versatile that the type of operation of the machine cannot readily be determined by merely observing the rate of use of the film or the foam-forming materials. Further, the machines may be operated in numerous and/or remote locations such that data cannot easily be collected from the machines by merely observing the operation of the machines.
Thus, there exists a need for an improved system and method for monitoring the use of consumable materials in a plurality of packaging machines and thereby providing an indication of the use of the machines in the different packaging modes.